Sound-amplifying means



June 1 1926. 7 1,586,659

-J. E. DAVIS SOUND AMPLIFYING MEANS Filed August 26, 1925 3 1] l9 j. v 1O 8/ {5 L41 f k 1 5 15 avwewboz Patented June 1, 1926.

UNITED STATES PATENT OFFICE.

JOHN E. DAVIS, OF BROOKLYN, NEW YORK.

SOUND-AMPLIFYING ivrEANs.

Application filed August 26, 1925. Serial No. 52,481.

This invention relates to means for amplifying sound waves, and is particularly adapted for use in the amplifying of sound waves emitted by the vibration of a diaphragm of a sound reproducing device, the

present invention being a further improvement of the sound amplifying means disclosed in my co-pending application Serial No. 688,714, filed Jan. 26, 1924:, wherein there is provided a receiver .for sound waves con nected to and supported from a sounding board extending around the receiver and being in the nature of a resonance chamber of truncated conical form and rectangular in cross section, or of truncated pyramidal form, closed at the smaller endgand said receiver and sounding board being made of panels .of relatively thin wood, such as spruce, having alternate relatively hard and soft or spongy growth rings quarter sawed across the naturalgrowth rings whereby said growth rings or the grain extend in parallel and alternate layers and the panels secured together at the longitudinal edge portions. The sound waves transmitted into the receiver set up a vibration of, the wall of said receiver which-vibrations, through the support and connection of the receiver with the sounding board, are transmitted to the sounding board not only vibrating the sounding board in consonance therewith butalso absorbing distorted vibrations induced by sound waves of overtones, and magnifying the sound waves of dominant and undertones.

It is the object of the present invention to improve the construction and arrangement of the sound receiver and resonance chamber or' sounding board whereby there will be a minimum resistance to the vibration thereof.

In carrying out the invention the resonance chamber or sounding board is constructed of panels the same as in my application hereinbefore referred to but instead of connecting the panels with the longitudinal edge portions in contact for the entire length thereof they are secured together at such edge portions adjacent the ends only with the intermediate portions cut away and thus providing spaces between said edge portions of the panel.

. The panels of the sound receiver are se- 65 cured together at the longitudinal edge portions ad acent one end only, to constitute t e ound. re e ng 1; a a d e gep r- .panels within the ends thereof are cut away ing the spaces 5 between adjacent panelstions from said connecting portion being free and out of contact to the opposite end, and by which portion of the receiver panels the receiver is-connected to and supported from the sounding board. 7 In the drawing accompanying and forming a part of this specification there is shown an embodiment of the invention wherein Figure l is a longitudinal sectional view of my improved sound. amplifying means and showing the manner of mounting the same in a cabinet; and

Figure 2 is a. perspective view with the cabinet partly removed and broken away. The embodiment of the invention illus trated in the drawing comprises a truncated cone shaped chamber 3, preferably of rectangular shape in cross section, forming in effect a truncated pyramidal resonance chamber, the wall of which is in effect asounding board, which chamber is constructed of panels, preferably of wood hav- 'ing alternating relative hard and soft spongy growth rings, spruce being preferred and having been found to function cfliciently for the purpose. It is understood that other wood having the same growth characteristic may be utilized. The wood is quarter sawed or sawed across the growth rings whereby the grain will extend in parallel relation longitudinally of the panels, and in the structure of the resonance cham her said grain will extend longitudinally of the axis thereof. The panels of said chamber are secured together practically without stress or strain and to oifera minimum resistance to the vibration thereof. For this purpose the longitudinal edge portion of the and the panels are connected together at adjacent opposite ends, as at 4, with the intermediate portions of the panels free and out of contact, the cut away portions form- .1 The small end of said chamber is closed by a wall 5. i

A sound receiver 6, which is preferably of conical tubular or pyramidal form with the wall diverging from the receiving end7 to the opposite end 8 and of rectangular shape in cross section, is mounted inthe resonance "chamber or sounding board 3 to extend thereinto from the larger end to adjacent but in spaced relation to the closed end 5', the receiving end of the sound receiver 6 being at the larger open end of the resonance chamber 3 with the latter extending around and in spaced relation to the receiver as clearly shown in the drawing. The receive; 6 is also made of panels secured together at the longitudinal edges at the inlet or receiving end 7 only, as at 9, with the marginal edge portion out way or under cut from the connecting portion to the end 8 whereby said edge portions will be in spaced relation, as at 10, and said marginal edges of the panels free. The receiver 6 is also made of wood having a grain consisting of alternating hard and soft or spongy layers extending longitudinally thereof.

To transmit the vibrations set up in the panels of the receiver 6 by the transmission of sound waves thereinto to the panels of the resonance chamber 3 in the receiver is connected to and supported from the panels of said chamber 3 by bridge pieces 11 engaged edgewise between the walls of the receiver 6 and resonance chamber 3 to extend longitudinally thereof and substantially midway between the" sides thereof, said bridge pieces having been found to function efiiciently by having the same engage for the full length thereof with the receiver 6 and secured thereto, as by gluing, and having a portion cut from the opposite longitudinal edge intermediate its ends, as at 12, whereby only a relatively small part of said edge of the bridge pieces and at opposite ends Will engage with the wall of the resonance chamber3. The receiver 6 and bridge pieces are held in position relative to the resonance chamber 3 substantially without stress or strain, screws 13 being shown for this purpose passing through the sounding board and engaging in the bridge pieces.

In order that the amplifier will function properly the amplifying unit, comprising the resonance chamber 3 with the sound wave receiver 6, is mounted in a support without stress or strain for which purpose it is mounted at the outer or enlarged end of the resonance chamber 3. In the present instance it is mounted in a cabinet 14 extending around in spaced relation and clos ing the sides and closed end 5 of the resonance chamber and having an open end at the enlarged open end of the said. chamber the latter being secured in said casing by screws 13 passing through. the edge portion of the wallet the resonance chamber substantially midway between thesides and engaging in the casing with a cushioning member 16 interposed between the resonance chamber and casing, ,as'clearly shown in the draw-' ing, 'A grille",17 'niayj 'be-.attached' to the open end ofth'e'casing'and amplifier, jThe' amplifier. may ,be used as a lmega- 'Phbfie ugm in nd mag i ying the sound. ofjhe'. man voice directlyin .which case jthe'jiiser' talks directly into..the f1"eceivngpt gf? of the receiver. 6, l j'. To'- u e the device for amplifying reproduced sounds, as by a vibratory diaphragm either mechanically or electrically operated, a diaphragm carrier or microphonic unit, designated in a general way at 18, is mounted directly in the receiving end of the receiver, for which purpose a reinforcement, as shown at 19, is arranged at the receiving end of the receiver, this reinforcement means consisting of a layer of wood similar to the material of which the receiveris made with the grain extending longitudinally of the receiver.

\Vhile I have illustrated and described one manner of constructing and arrangement of my improved sound amplifier it will be obvious that the invention is not to be limited to such construction and arrangement and that variations and modifications may be made in structure and form and that portions of the invention may be used with-' out others and come within the scope of the invention.

Having thus described my invention I claim:

1. In a sound amplifier, a resonance chamber of truncated conical form comprising panels secured together at the longitudinal edge portions adjacent the ends only with the longitudinal edge portions cut away intermediate said securing portions for the purpose specified.

2. In a sound amplifier, a resonance chamber of truncated conical and rectangular shape in cross section, the side walls of said chamber being constructed of panels having cut away portions intermediate the ends and secured together at the edge portion at the ends of the cut away portions, and a closure secured to the panels at the smaller end.

3. In a sound amplifier, a resonance chamber of truncated conical and rectangular shape in cross section, the side walls of said chamber being constructed of panels having cut away portions intermediate the ends and secured together at the edge portion at the ends of the cut away portions, and a sound receiver and support for a sound reproducer within and supported by the panels of the resonance chamber.

4. In a sound amplifier, a resonance chamber of truncated conical form constructed of panels connected together at the longitudinal edge portions adjacent the ends and the edge portions of the panels intermediate the connections thereof being free and out of contact to connect the panels without stress or strain, an open end cabinet, and means to mount the resonance chamber in the cabinet substantially without stress 'or strain With the-larger end thereof at the open end of the cabinets .,5. In a sound; amplifier, aresonance chamber. of truncated conical form' constructed of panels secured together at the l g t e ge re i es-adja en t e e with the edge portions of the panels intermediate the connecting portions cut away, a closure secured to the panels at the smaller end, a tubular sound receiver and support for a sound reproducer extending into the resonance chamber from the larger end and centrally thereof, and bridge pieces interposed between the sound receiver and panels of the resonance chamber to support the sound receiver and connect the same with the panels of the resonance chamber.

(3. In a sound amplifier, a resonance chamber of truncated conical form constructed of panels secured together at the longitudinal edge portions adjacent the ends with the edge portions of the panels intermediate the connecting portions cut away, a closure secured to the panels at the smaller end, a tubular sound receiver and support for a sound reproducer extending into the resonance chamber from the larger end and centrally thereof, bridge pieces interposed between the sound receiver and panels of the resonance chamber to support the sound receiver and connect the same with the panels of the resonance chamber, an open end cabinet, and means to support. the resonance chamber without stress or strain at the larger end and with said end at the open end of the cabinet.

7. In a sound amplifier, a resonance chamber of truncated conical form con structed of panelssecured together at the longitudinal edge portions adjacent the ends with the edge portions of the panels intermediate the connecting portions cut away, a tubular sound receiver and support for a sound reproducer, said receiver being constructed of panels secured together at the longitudinal edge portion adjacent one end and the edge portion of the panels from such connection being free to the opposite end of the receiver, and means extending longitudinally of the receiver and resonance chamber to connect and support the receiver from said chamber at the free end portions of the panels.

8. In a sound amplifier,- a resonance chamber of truncated conical form constructed of panels connected together at the hmgitudinal edge portions adjacent the ends with the portions of the panels intermediate the'connections thereof tree and out of contact, a closure for the smaller end of said chamber, a conical tubular member constructed of panels connected together at. the. edge portions adjacent the smaller end and arranged at said end as a support for a sound reproducer, and the edge portions of the panels of said tubular member from the point of connection extending to the larger end being free and out of contact with adjacentpanels, bridge pieces to support the tubular member within and from the resonance chamber with the smaller end of the tubular member at the larger end of the.

resonance chamber and the larger end of the tubular member adjacent the smaller closed end of the resonance chamber, said bridge pieces being arranged in edgewise relation to extend longitudinally of and midway between the sides of the panels of the resonance chamber and tubular member, and means to support the resonance chamber substantially without stress or strain.

9. In a sound amplifier constructed and arranged in accordance with claim 8, an open end cabinet in which the resonance chamber is mounted at the open end without stress or strain with said end at the open end of the cabinet.

Signed at New York city, in the county of New York and State of New York, this 1stday of August, 1925.

JOHN DAVIS. 

